Cable hangers are commonly used to secure cables to structural members of antenna towers and or along tunnel walls. Generally, each cable is attached to a structural member by cable hangers mounted at periodically-spaced attachment points.
Antenna towers and or tunnels may be crowded due to the large numbers of cables required for signal-carrying. Over time, as systems are added, upgraded and/or expanded, installation of additional cables may be required. To conserve space, it may be desirable for each set of cable hangers to secure more than a single cable. Certain cable hangers have been constructed to secure multiple cables; other cable hangers have a stackable construction that permits multiple cable hangers to be interlocked extending outwardly from each mounting point/structural member. Stacked and multiple-cable hangers significantly increase the number of cables mountable to a single attachment point.
One popular stackable cable hanger is discussed in U.S. Pat. No. 8,191,836 to Korczak, the disclosure of which is hereby incorporated herein by reference in its entirety. One such cable hanger, designated broadly at 10, is shown in FIGS. 1 and 2. The hanger 10 includes curved arms 5 that extend from a flat base 6. Locking projections 7 extend from the free ends of the arms 5. As can be seen in FIGS. 1 and 2, the locking projections 7 are inserted into a reinforced hole 8 in a tower structure or adapter 4 to mount the hanger 10 thereon. The base 6 of the hanger 10 includes a reinforced hole 9 that can receive the projections of another hanger 10 to mount a second cable.
As can be best seen in FIG. 2, the arms 5 include two arcuate sections 14 that together generally define a circle within which a cable can reside. Two cantilevered tabs 12 extend radially inwardly and toward the base 6 at one end of the arcuate sections 14, and two cantilevered tabs 16 extend radially inwardly and toward the base 6 from the opposite ends of the arcuate sections 14. The cantilevered tabs 12, 16 are deployed to deflect radially outwardly when the hanger 10 receives a cable for mounting; this deflection generates a radially inward force from each tab 12, 16 that grips the jacket of the cable.
Hangers can be “stacked” onto each other by inserting the locking projections 7 of one hanger into the large hole 9 of the next hanger. One variety of cable hanger of this type is the SNAP-STAK® hanger, available from CommScope, Inc. (Joliet, Ill.).
The SNAP-STAK® hanger is offered in multiple sizes that correspond to the outer diameters of different cables. This arrangement has been suitable for use with RF coaxial cables, which tend to be manufactured in only a few different outer diameters; however, the arrangement has been less desirable for fiber optic cables, which tend to be manufactured in a much greater variety of diameters. Moreover, fiber optic cables tend to be much heavier than coaxial cables (sometimes as much as three times heavier per unit foot), which induces greater load and stress on the hangers.
Multiple approaches to addressing this issue are offered in co-assigned and co-pending U.S. Patent Publication No. 2016/0281881 to Vaccaro, the disclosure of which is hereby incorporated herein by reference in full. One cable hanger discussed in this publication is shown in FIGS. 3 and 4 and designated broadly at 610 therein. The cable hanger 610 is somewhat similar to the cable hanger 10, inasmuch as it has a base 606, curved arms 605 and locking projections 607 that resemble those of the hanger 10 discussed above. However, the cable hanger 610 also has flex members 618 that define chords across the arcuate sections 614 of the arms 605. As can be seen in FIG. 4, cantilevered gripping members 612, 616 extend from the flex members 618 and into the cable-gripping space S within the arms 605. It can also be seen in FIG. 3 that the flex members 618 are tripartite, with two vertically offset horizontal runs 618a, 618c merging with the arcuate sections 614 of the arms 605 and a vertical run 618b extending between the horizontal runs 618a, 618c. The gripping members 612, 616 extend from opposite sides of the vertical run 618b and are vertically offset from each other.
In use, the cable hanger 610 is employed in the same manner as the cable hanger 10; a cable is inserted into the space S between the arms 605, which are then closed around the cable as the locking projections 607 are inserted into a mounting hole. The cantilevered gripping members 612, 616 can help to grip and to center the cable within the space S. The presence of the flex members 618, which are fixed end beams rather than cantilevered tabs, can provide additional gripping force beyond that of the cable hanger 10.
Either of the cable hangers 10, 610 may be subjected to loading from sources besides the weight of cables, including wind, particularly when the cable hangers are mounted on tall antenna towers or other mounting structures that are positioned well above the ground. The additional loading can make the cable hanger susceptible to slipping or even becoming dislodged. To address this possibility, a “dogbone”-shaped support (designated at 50 in FIG. 5) can be inserted between fee ends of the arms 5 of a cable hanger 10 to provide additional stability. More specifically, the support 50 has a shaft 51 with bulging ends 52. A split latch 53 projects from one side of the shaft 51. As can be seen in FIGS. 6 and 7, the support 50 is inserted between the free ends of the arms 5 near the locking projections 7 of the cable hanger 10, with the bulging ends 52 above and below the arms 5, and the split latch 53 extending into the mounting hole 8 of the adapter 4 or other mounting structure. The presence of the support 50 helps to prevent the locking projections 7 from deflecting inwardly under load, which deflection could result in unintended dislodging of the mounted cable hanger.
It may be desirable to provide additional configurations of supports for cable hangers that may be used with a cable hanger.